Celebration is a befitting retrospective for the shapeshifting international icon: a double-length, 36-song greatest-hits collection. Every era, every reinvention, every musical nuance is captured here, from the '80s gleam of "Burning Up" and "Like a Virgin" to the ghetto-fab swagger of "Music" and the embrace of dance music culture ushered in by "Ray of Light." Among the extra goodies collected here are the Benny Benassi–produced title track and a Madonna/Lil Wayne collaboration (“Revolver”).